Soy Isoflavones May Help Protect Bones During Menopause

Concerned about soy? Another study adds to the debate about whether consuming soy is a healthy choice, finding that it may benefit menopausal women who are at risk for osteoporosis. Presented at the Society for Endocrinology’s 2015 annual conference, the study randomly assigned 200 women in early menopause (2 years within onset of menopause) to one of two groups: the first group received 30 grams of soy protein plus 66 mg of soy isoflavones daily, while the second group received only 30 grams of soy protein daily. After six months, here is what the researchers found:

Women who consumed soy protein plus isoflavones had significantly lower levels of a protein related to bone breakdown in their blood, compared to women who consumed soy protein alone. Lower levels of this protein are thought to indicate a slower rate of bone loss that could, over time, lead to a reduced risk of osteoporosis.

In addition, compared to women in the soy protein-only group, women in the isoflavone group had beneficial reductions in levels of fasting glucose and fasting insulin—markers of carbohydrate metabolism that are closely linked to cardiovascular disease risk.

These findings show that taking soy protein plus isoflavones might slow bone loss in the short-term, but longer studies that measure actual changes in bone mineral density are needed to determine whether this effect translates into protection against osteoporosis. One possible explanation for soy isoflavones’ benefits is that they are similar in chemical structure to human estrogen, and so might be able to stimulate bone regenerative activity by interacting with estrogen receptors. This could be especially important after menopause when estrogen production is at its lowest. It is important to note that, while a typical Asian diet contains a similar amount of soy isoflavones as was used in this study, a typical Western diet only contains a fraction of that amount (about 2–16 mg).